1. Field of the Invention
The present invention relates to a recording sheet stacking tray.
2. Discussion of the Background
Recording sheets stacked on a recording sheet stacking tray are fed into the image forming apparatus. Conventionally, for this purpose, a sheet feeder is disposed on the downstream side of a sheet feed direction of the recording sheets. The sheet feeder includes a sheet feed roller and an elevating plate to upwardly press the recording sheets against the sheet feed roller. In this sheet feeder, when the elevating plate presses the recording sheets upwardly, the upper surface of the elevating plate is inclined downwardly to the upstream side of the sheet feed direction. Consequently, the recording sheets slip down the inclined surface of the elevating plate and move backwardly to the reverse side (upstream side) of the sheet feed direction. As a result, the recording sheets move away from the sheet feed roller, which may unfortunately cause a sheet feed error. Such a backward movement of recording sheets is frequently noticed in the case of recording sheets having a small size and high rigidity.
In order to prevent the above-described backward movement of recording sheets and stabilize the sheet feed operation, there exists a recording sheet stacking tray including a trailing edge restriction plate. The trailing edge restriction plate restricts trailing edges of the recording sheets stacked on the recording sheet stacking tray in accordance with a size of the recording sheets. For example, as disclosed in Japanese Unexamined Patent Application Publication No. 2012-188233, a groove in a sheet feed direction is formed in the recording sheet stacking tray in such a manner that the trailing edge restriction plate is movable in the sheet feed direction while being guided by the groove. As disclosed in Japanese Unexamined Patent Application Publication No. 2009-154977, another example of the recording sheet stacking tray includes an external trailing edge restriction plate detachably attached to insertion recessed portions in the recording sheet stacking tray corresponding to a plurality of sizes of recording sheets.
However, the trailing edge restriction plate, as disclosed in Japanese Unexamined Patent Application Publication No. 2012-188233, requires the groove to guide the trailing edge restriction plate formed in the upper surface of the recording sheet stacking tray. Therefore, the upper surface of the recording sheet stacking tray is not made flat. This may disadvantageously make unstable a stack state of the recording sheets. Moreover, a large stroke amount is necessary to slide the trailing edge restriction plate to a desired restriction position of the recording sheets. This may unfavorably degrade operability by a user.
An operation of the trailing edge restriction plate, as disclosed in Japanese Unexamined Patent Application Publication No. 2009-154977, involves labor and time. This is because each time recording sheets of a different size are used, the trailing edge restriction plate is detached from the insertion recessed portion and attached to another position. Furthermore, the recording sheet stacking tray has no place in which the trailing edge restriction plate is contained. Consequently, the trailing edge restriction plate, which is kept separately, may be unfortunately lost when not used.
The present invention has been made in view of the above-described problems. It is a technical object of the present invention to provide a recording sheet stacking tray including a trailing edge restriction member that is readily moved to a desired restriction position and contained in the recording sheet stacking tray while an upper surface of the recording sheet stacking tray is made flat.